These are TakaraTomy toys (and maybe some significant licensed items) currently known from official sources, scheduled for release in MARCHin Japan (as well as in Asia as most Japanese Transformers toys are also released through Hasbro Hong Kong).

Dates and details can change at any time - Approximate yen prices listed are just a rough guide to their retail price in Japan.
Links were active at the time they were first added and are only there for reference/proof of details - I do NOT endorse or promote any of those businesses.
(posting corrections or additions are greatly appreciated)

I think the Adventure line (Robots In Disguise) is over in Japan... as the last release was in November, and we have nothing known for the next few months, which would be a six month break if there are more.

This shouldn't be due to the Movie line this year, as this six months is before the Movie toys come out, and the Adventure toys are just redecos of Hasbro toys, so there would be very little resources needed for this line.

And the Legends (Generations) line is slowing right down too, with only four general release items for the first eight months of the year... and unless there are movie toys that are exclusive to Japan (in design, not just redecos), the Legends line shouldn't be suffering either from the Movie year.

There just isn't a lot of "new" product this year from TakaraTomy so far this year, when you compare the first 4-5 months of this year to last year.
I think it just means it is another "down year" for Transformers by TakaraTomy, like how they scale right back every few years, then the Brand grows for a few years.